Inductive proximity switch belongs to a position sensor with switch output, which is composed of an LC high-frequency oscillator and an amplification processing circuit. It uses a metal object to generate eddy currents inside the object when approaching the oscillating induction head that can generate electromagnetic fields. This eddy current reacts on the proximity switch, causing the oscillation ability of the proximity switch to decay, causing changes in the parameters of the internal circuit, thereby identifying whether a metal object is approaching and controlling the on-off of the switch. The object that this proximity switch can detect must be a metal object.

2、 Capacitive proximity switch series
Capacitive proximity switches are also a type of position sensor with switch output. Their measuring head is usually a plate that forms the capacitor, and the other plate is the object itself. When the object moves towards the proximity switch, the dielectric constant of the object and proximity switch changes, causing the circuit state connected to the measuring head to also change, thereby controlling the on and off of the switch. The detection objects of this proximity switch are not limited to metal conductors, but can also be insulated liquid or powder objects. When detecting objects with lower dielectric constant, the multi turn potentiometer (located at the back of the switch) can be adjusted clockwise to increase sensing sensitivity. Generally, the potentiometer is adjusted to make the capacitive proximity switch operate at the position of 0.7-0.8Sn.

3、 Working principle of Hall switch
When a metal or semiconductor thin sheet with an electric current is placed vertically in a magnetic field, there will be a potential difference between the two ends of the sheet, which is called the Hall effect. It can be seen that the sensitivity of the Hall effect is directly proportional to the magnetic induction intensity of the external magnetic field.

Hall switch belongs to this type of active magneto electric converter device, which is based on the Hall effect principle and is manufactured using integrated packaging and assembly technology. It can easily convert magnetic input signals into electrical signals in practical applications, while also meeting the requirements of easy operation and reliability in industrial applications.

4、 Working principle of magnetic switches
A magnetic switch is a proximity sensor that responds to a permanent magnetic field. The operating distance is greater than that of an inductive sensor. The response curve is related to the direction of the permanent magnetic field.







When a target (permanent magnet or external magnetic field) approaches, the magnetic conductivity of the coil core (the inductance L of the coil is determined by it) decreases, the inductance of the coil also decreases, and the Q value increases. Excite the oscillator to oscillate and increase the oscillation current. When a magnetic target approaches, the current consumption of the magnetic sensor increases accordingly.

Advantages of magnetic sensors compared to inductive sensors:
--Sensors can be installed in metal

--There are no requirements for installing sensors side by side

--The top of the sensor (sensing surface) can be made of metal

--Sensors can pass through metal detection